76 lines
2 KiB
Markdown
76 lines
2 KiB
Markdown
---
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creation date: 2023-04-10
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tags: [note,firewall,iptables,linux]
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---
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Change `icmp` to `icmp -j REJECT` to not allow `ping` command.
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## IPv4
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Put into `/etc/iptables/iptables.rules`. Pay attention to blank line at the end.
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```shell
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*filter
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:INPUT DROP [0:0]
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:FORWARD DROP [0:0]
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:OUTPUT ACCEPT [0:0]
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:TCP - [0:0]
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:UDP - [0:0]
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-A INPUT -m conntrack --ctstate RELATED,ESTABLISHED -j ACCEPT
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-A INPUT -i lo -j ACCEPT
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-A INPUT -m conntrack --ctstate INVALID -j DROP
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-A INPUT -p icmp -m icmp --icmp-type 8 -m conntrack --ctstate NEW -j ACCEPT
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-A INPUT -p udp -m conntrack --ctstate NEW -j UDP
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-A INPUT -p tcp --tcp-flags FIN,SYN,RST,ACK SYN -m conntrack --ctstate NEW -j TCP
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-A INPUT -p udp -j REJECT --reject-with icmp-port-unreachable
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-A INPUT -p tcp -j REJECT --reject-with tcp-reset
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-A INPUT -j REJECT --reject-with icmp-proto-unreachable
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COMMIT
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```
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Enable `iptables.service`. Verify result with `sudo iptables -S`.
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Add `4713` (pulseaudio) rule if necessary.
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```shell
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-A INPUT -m state --state NEW -m tcp -p tcp --dport 4713 -j ACCEPT
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```
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## IPv6
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Put into `/etc/iptables/ip6tables.rules`. Pay attention to blank line at the end.
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```shell
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*filter
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:INPUT DROP [0:0]
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:FORWARD DROP [0:0]
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:OUTPUT ACCEPT [0:0]
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:TCP - [0:0]
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:UDP - [0:0]
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-A INPUT -m conntrack --ctstate RELATED,ESTABLISHED -j ACCEPT
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-A INPUT -i lo -j ACCEPT
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-A INPUT -m conntrack --ctstate INVALID -j DROP
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-A INPUT -s fe80::/10 -p ipv6-icmp -j ACCEPT
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-A INPUT -p udp --sport 547 --dport 546 -j ACCEPT
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-A INPUT -p udp -m conntrack --ctstate NEW -j UDP
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-A INPUT -p tcp -m tcp --tcp-flags FIN,SYN,RST,ACK SYN -m conntrack --ctstate NEW -j TCP
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-A INPUT -p udp -j REJECT --reject-with icmp6-adm-prohibited
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-A INPUT -p tcp -j REJECT --reject-with tcp-reset
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-A INPUT -j REJECT --reject-with icmp6-adm-prohibited
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-A INPUT -p ipv6-icmp -m icmp6 --icmpv6-type 128 -m conntrack --ctstate NEW -j ACCEPT
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COMMIT
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```
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Enable `ip6tables.service`. Verify result with `sudo ip6tables -S`.
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Add `4713` (pulseaudio) rule if necessary.
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```shell
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-A INPUT -m state --state NEW -m tcp -p tcp --dport 4713 -j ACCEPT
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```
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